A typical brake assembly for a motor vehicle includes a caliper assembly and one or more brake pads. The caliper assembly includes a frame or body, which is mounted to the structure of the vehicle and a caliper piston. The caliper piston is movably mounted to the caliper body so as to be selectively engagable with the brake pads to cause the brake pads to frictionally engage an element, such as a vehicle rotor, to thereby slow or stop the vehicle.
The caliper body includes a piston bore into which the piston is received. A boot-type seal is typically employed to seal around the perimeter of both the piston bore and the caliper piston to inhibit moisture, dirt, debris and other contaminants from entering the piston bore and potentially damaging the caliper body and/or caliper piston. Despite the widespread use of such boot-type seals, several drawbacks are known and thus, such boot-type seals are susceptible to improvement.
One such drawback concerns the buildup of fluid pressure within such boot-type seals. As those of ordinary skill in the art will appreciate, heat generated during the operation of the brake assembly causes the air that is trapped by the boot-type seal to expand. In especially severe instances, it may be possible for the boot-type seal to expand and deleteriously contact another portion of the brake assembly, causing the boot-type seal to burn, melt, or otherwise undergo a shortening of its useful life as a result of thermal cycling at elevated temperatures. If severe enough, such damage may lead to a failure of the boot-type seal through which dirt, debris, moisture and other contaminants may be transmitted.